Wind, Sun, and the Weather examines the first of renewable energy’s two major drawbacks: weather-induced intermittency. Graphical illustrations show that when wind and solar energy supply is subtracted from total electricity demand, the residual demand must be met by dispatchable backup power from nuclear, hydroelectric, or fossil fueled plants. Supplying residual demand is expensive and fraught with difficulties, for the backup plants must rapidly ramp up and down in power frequently and operate at uneconomically low power levels for extended durations. Renewables’ small load factors, solar power’s deficit caused by winter’s dimmed sunlight, and other aspects of intermittency are included in the narrative.